Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c
index 030c98f..eb76a82 100644
--- a/drivers/android/binder_alloc.c
+++ b/drivers/android/binder_alloc.c
@@ -1,18 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /* binder_alloc.c
  *
  * Android IPC Subsystem
  *
  * Copyright (C) 2007-2017 Google, Inc.
- *
- * This software is licensed under the terms of the GNU General Public
- * License version 2, as published by the Free Software Foundation, and
- * may be copied, distributed, and modified under those terms.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
  */
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
@@ -29,6 +20,9 @@
 #include <linux/list_lru.h>
 #include <linux/ratelimit.h>
 #include <asm/cacheflush.h>
+#include <linux/uaccess.h>
+#include <linux/highmem.h>
+#include <linux/sizes.h>
 #include "binder_alloc.h"
 #include "binder_trace.h"
 
@@ -67,9 +61,8 @@
 				       struct binder_buffer *buffer)
 {
 	if (list_is_last(&buffer->entry, &alloc->buffers))
-		return (u8 *)alloc->buffer +
-			alloc->buffer_size - (u8 *)buffer->data;
-	return (u8 *)binder_buffer_next(buffer)->data - (u8 *)buffer->data;
+		return alloc->buffer + alloc->buffer_size - buffer->user_data;
+	return binder_buffer_next(buffer)->user_data - buffer->user_data;
 }
 
 static void binder_insert_free_buffer(struct binder_alloc *alloc,
@@ -119,9 +112,9 @@
 		buffer = rb_entry(parent, struct binder_buffer, rb_node);
 		BUG_ON(buffer->free);
 
-		if (new_buffer->data < buffer->data)
+		if (new_buffer->user_data < buffer->user_data)
 			p = &parent->rb_left;
-		else if (new_buffer->data > buffer->data)
+		else if (new_buffer->user_data > buffer->user_data)
 			p = &parent->rb_right;
 		else
 			BUG();
@@ -136,17 +129,17 @@
 {
 	struct rb_node *n = alloc->allocated_buffers.rb_node;
 	struct binder_buffer *buffer;
-	void *kern_ptr;
+	void __user *uptr;
 
-	kern_ptr = (void *)(user_ptr - alloc->user_buffer_offset);
+	uptr = (void __user *)user_ptr;
 
 	while (n) {
 		buffer = rb_entry(n, struct binder_buffer, rb_node);
 		BUG_ON(buffer->free);
 
-		if (kern_ptr < buffer->data)
+		if (uptr < buffer->user_data)
 			n = n->rb_left;
-		else if (kern_ptr > buffer->data)
+		else if (uptr > buffer->user_data)
 			n = n->rb_right;
 		else {
 			/*
@@ -164,7 +157,7 @@
 }
 
 /**
- * binder_alloc_buffer_lookup() - get buffer given user ptr
+ * binder_alloc_prepare_to_free() - get buffer given user ptr
  * @alloc:	binder_alloc for this proc
  * @user_ptr:	User pointer to buffer data
  *
@@ -186,9 +179,9 @@
 }
 
 static int binder_update_page_range(struct binder_alloc *alloc, int allocate,
-				    void *start, void *end)
+				    void __user *start, void __user *end)
 {
-	void *page_addr;
+	void __user *page_addr;
 	unsigned long user_page_addr;
 	struct binder_lru_page *page;
 	struct vm_area_struct *vma = NULL;
@@ -263,18 +256,7 @@
 		page->alloc = alloc;
 		INIT_LIST_HEAD(&page->lru);
 
-		ret = map_kernel_range_noflush((unsigned long)page_addr,
-					       PAGE_SIZE, PAGE_KERNEL,
-					       &page->page_ptr);
-		flush_cache_vmap((unsigned long)page_addr,
-				(unsigned long)page_addr + PAGE_SIZE);
-		if (ret != 1) {
-			pr_err("%d: binder_alloc_buf failed to map page at %pK in kernel\n",
-			       alloc->pid, page_addr);
-			goto err_map_kernel_failed;
-		}
-		user_page_addr =
-			(uintptr_t)page_addr + alloc->user_buffer_offset;
+		user_page_addr = (uintptr_t)page_addr;
 		ret = vm_insert_page(vma, user_page_addr, page[0].page_ptr);
 		if (ret) {
 			pr_err("%d: binder_alloc_buf failed to map page at %lx in userspace\n",
@@ -312,8 +294,6 @@
 		continue;
 
 err_vm_insert_page_failed:
-		unmap_kernel_range((unsigned long)page_addr, PAGE_SIZE);
-err_map_kernel_failed:
 		__free_page(page->page_ptr);
 		page->page_ptr = NULL;
 err_alloc_page_failed:
@@ -368,8 +348,8 @@
 	struct binder_buffer *buffer;
 	size_t buffer_size;
 	struct rb_node *best_fit = NULL;
-	void *has_page_addr;
-	void *end_page_addr;
+	void __user *has_page_addr;
+	void __user *end_page_addr;
 	size_t size, data_offsets_size;
 	int ret;
 
@@ -467,15 +447,15 @@
 		     "%d: binder_alloc_buf size %zd got buffer %pK size %zd\n",
 		      alloc->pid, size, buffer, buffer_size);
 
-	has_page_addr =
-		(void *)(((uintptr_t)buffer->data + buffer_size) & PAGE_MASK);
+	has_page_addr = (void __user *)
+		(((uintptr_t)buffer->user_data + buffer_size) & PAGE_MASK);
 	WARN_ON(n && buffer_size != size);
 	end_page_addr =
-		(void *)PAGE_ALIGN((uintptr_t)buffer->data + size);
+		(void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data + size);
 	if (end_page_addr > has_page_addr)
 		end_page_addr = has_page_addr;
-	ret = binder_update_page_range(alloc, 1,
-	    (void *)PAGE_ALIGN((uintptr_t)buffer->data), end_page_addr);
+	ret = binder_update_page_range(alloc, 1, (void __user *)
+		PAGE_ALIGN((uintptr_t)buffer->user_data), end_page_addr);
 	if (ret)
 		return ERR_PTR(ret);
 
@@ -488,7 +468,7 @@
 			       __func__, alloc->pid);
 			goto err_alloc_buf_struct_failed;
 		}
-		new_buffer->data = (u8 *)buffer->data + size;
+		new_buffer->user_data = (u8 __user *)buffer->user_data + size;
 		list_add(&new_buffer->entry, &buffer->entry);
 		new_buffer->free = 1;
 		binder_insert_free_buffer(alloc, new_buffer);
@@ -514,8 +494,8 @@
 	return buffer;
 
 err_alloc_buf_struct_failed:
-	binder_update_page_range(alloc, 0,
-				 (void *)PAGE_ALIGN((uintptr_t)buffer->data),
+	binder_update_page_range(alloc, 0, (void __user *)
+				 PAGE_ALIGN((uintptr_t)buffer->user_data),
 				 end_page_addr);
 	return ERR_PTR(-ENOMEM);
 }
@@ -550,14 +530,15 @@
 	return buffer;
 }
 
-static void *buffer_start_page(struct binder_buffer *buffer)
+static void __user *buffer_start_page(struct binder_buffer *buffer)
 {
-	return (void *)((uintptr_t)buffer->data & PAGE_MASK);
+	return (void __user *)((uintptr_t)buffer->user_data & PAGE_MASK);
 }
 
-static void *prev_buffer_end_page(struct binder_buffer *buffer)
+static void __user *prev_buffer_end_page(struct binder_buffer *buffer)
 {
-	return (void *)(((uintptr_t)(buffer->data) - 1) & PAGE_MASK);
+	return (void __user *)
+		(((uintptr_t)(buffer->user_data) - 1) & PAGE_MASK);
 }
 
 static void binder_delete_free_buffer(struct binder_alloc *alloc,
@@ -572,7 +553,8 @@
 		to_free = false;
 		binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 				   "%d: merge free, buffer %pK share page with %pK\n",
-				   alloc->pid, buffer->data, prev->data);
+				   alloc->pid, buffer->user_data,
+				   prev->user_data);
 	}
 
 	if (!list_is_last(&buffer->entry, &alloc->buffers)) {
@@ -582,23 +564,24 @@
 			binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 					   "%d: merge free, buffer %pK share page with %pK\n",
 					   alloc->pid,
-					   buffer->data,
-					   next->data);
+					   buffer->user_data,
+					   next->user_data);
 		}
 	}
 
-	if (PAGE_ALIGNED(buffer->data)) {
+	if (PAGE_ALIGNED(buffer->user_data)) {
 		binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 				   "%d: merge free, buffer start %pK is page aligned\n",
-				   alloc->pid, buffer->data);
+				   alloc->pid, buffer->user_data);
 		to_free = false;
 	}
 
 	if (to_free) {
 		binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 				   "%d: merge free, buffer %pK do not share page with %pK or %pK\n",
-				   alloc->pid, buffer->data,
-				   prev->data, next ? next->data : NULL);
+				   alloc->pid, buffer->user_data,
+				   prev->user_data,
+				   next ? next->user_data : NULL);
 		binder_update_page_range(alloc, 0, buffer_start_page(buffer),
 					 buffer_start_page(buffer) + PAGE_SIZE);
 	}
@@ -624,8 +607,8 @@
 	BUG_ON(buffer->free);
 	BUG_ON(size > buffer_size);
 	BUG_ON(buffer->transaction != NULL);
-	BUG_ON(buffer->data < alloc->buffer);
-	BUG_ON(buffer->data > alloc->buffer + alloc->buffer_size);
+	BUG_ON(buffer->user_data < alloc->buffer);
+	BUG_ON(buffer->user_data > alloc->buffer + alloc->buffer_size);
 
 	if (buffer->async_transaction) {
 		alloc->free_async_space += size + sizeof(struct binder_buffer);
@@ -636,8 +619,9 @@
 	}
 
 	binder_update_page_range(alloc, 0,
-		(void *)PAGE_ALIGN((uintptr_t)buffer->data),
-		(void *)(((uintptr_t)buffer->data + buffer_size) & PAGE_MASK));
+		(void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data),
+		(void __user *)(((uintptr_t)
+			  buffer->user_data + buffer_size) & PAGE_MASK));
 
 	rb_erase(&buffer->rb_node, &alloc->allocated_buffers);
 	buffer->free = 1;
@@ -693,7 +677,6 @@
 			      struct vm_area_struct *vma)
 {
 	int ret;
-	struct vm_struct *area;
 	const char *failure_string;
 	struct binder_buffer *buffer;
 
@@ -704,29 +687,12 @@
 		goto err_already_mapped;
 	}
 
-	area = get_vm_area(vma->vm_end - vma->vm_start, VM_ALLOC);
-	if (area == NULL) {
-		ret = -ENOMEM;
-		failure_string = "get_vm_area";
-		goto err_get_vm_area_failed;
-	}
-	alloc->buffer = area->addr;
-	alloc->user_buffer_offset =
-		vma->vm_start - (uintptr_t)alloc->buffer;
+	alloc->buffer = (void __user *)vma->vm_start;
 	mutex_unlock(&binder_alloc_mmap_lock);
 
-#ifdef CONFIG_CPU_CACHE_VIPT
-	if (cache_is_vipt_aliasing()) {
-		while (CACHE_COLOUR(
-				(vma->vm_start ^ (uint32_t)alloc->buffer))) {
-			pr_info("%s: %d %lx-%lx maps %pK bad alignment\n",
-				__func__, alloc->pid, vma->vm_start,
-				vma->vm_end, alloc->buffer);
-			vma->vm_start += PAGE_SIZE;
-		}
-	}
-#endif
-	alloc->pages = kcalloc((vma->vm_end - vma->vm_start) / PAGE_SIZE,
+	alloc->buffer_size = min_t(unsigned long, vma->vm_end - vma->vm_start,
+				   SZ_4M);
+	alloc->pages = kcalloc(alloc->buffer_size / PAGE_SIZE,
 			       sizeof(alloc->pages[0]),
 			       GFP_KERNEL);
 	if (alloc->pages == NULL) {
@@ -734,7 +700,6 @@
 		failure_string = "alloc page array";
 		goto err_alloc_pages_failed;
 	}
-	alloc->buffer_size = vma->vm_end - vma->vm_start;
 
 	buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 	if (!buffer) {
@@ -743,7 +708,7 @@
 		goto err_alloc_buf_struct_failed;
 	}
 
-	buffer->data = alloc->buffer;
+	buffer->user_data = alloc->buffer;
 	list_add(&buffer->entry, &alloc->buffers);
 	buffer->free = 1;
 	binder_insert_free_buffer(alloc, buffer);
@@ -758,9 +723,7 @@
 	alloc->pages = NULL;
 err_alloc_pages_failed:
 	mutex_lock(&binder_alloc_mmap_lock);
-	vfree(alloc->buffer);
 	alloc->buffer = NULL;
-err_get_vm_area_failed:
 err_already_mapped:
 	mutex_unlock(&binder_alloc_mmap_lock);
 	binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
@@ -806,7 +769,7 @@
 		int i;
 
 		for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
-			void *page_addr;
+			void __user *page_addr;
 			bool on_lru;
 
 			if (!alloc->pages[i].page_ptr)
@@ -819,12 +782,10 @@
 				     "%s: %d: page %d at %pK %s\n",
 				     __func__, alloc->pid, i, page_addr,
 				     on_lru ? "on lru" : "active");
-			unmap_kernel_range((unsigned long)page_addr, PAGE_SIZE);
 			__free_page(alloc->pages[i].page_ptr);
 			page_count++;
 		}
 		kfree(alloc->pages);
-		vfree(alloc->buffer);
 	}
 	mutex_unlock(&alloc->mutex);
 	if (alloc->vma_vm_mm)
@@ -839,7 +800,7 @@
 				struct binder_buffer *buffer)
 {
 	seq_printf(m, "%s %d: %pK size %zd:%zd:%zd %s\n",
-		   prefix, buffer->debug_id, buffer->data,
+		   prefix, buffer->debug_id, buffer->user_data,
 		   buffer->data_size, buffer->offsets_size,
 		   buffer->extra_buffers_size,
 		   buffer->transaction ? "active" : "delivered");
@@ -939,6 +900,7 @@
 				       struct list_lru_one *lru,
 				       spinlock_t *lock,
 				       void *cb_arg)
+	__must_hold(lock)
 {
 	struct mm_struct *mm = NULL;
 	struct binder_lru_page *page = container_of(item,
@@ -958,14 +920,13 @@
 
 	index = page - alloc->pages;
 	page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE;
+
+	mm = alloc->vma_vm_mm;
+	if (!mmget_not_zero(mm))
+		goto err_mmget;
+	if (!down_read_trylock(&mm->mmap_sem))
+		goto err_down_read_mmap_sem_failed;
 	vma = binder_alloc_get_vma(alloc);
-	if (vma) {
-		if (!mmget_not_zero(alloc->vma_vm_mm))
-			goto err_mmget;
-		mm = alloc->vma_vm_mm;
-		if (!down_write_trylock(&mm->mmap_sem))
-			goto err_down_write_mmap_sem_failed;
-	}
 
 	list_lru_isolate(lru, item);
 	spin_unlock(lock);
@@ -973,19 +934,15 @@
 	if (vma) {
 		trace_binder_unmap_user_start(alloc, index);
 
-		zap_page_range(vma,
-			       page_addr + alloc->user_buffer_offset,
-			       PAGE_SIZE);
+		zap_page_range(vma, page_addr, PAGE_SIZE);
 
 		trace_binder_unmap_user_end(alloc, index);
-
-		up_write(&mm->mmap_sem);
-		mmput(mm);
 	}
+	up_read(&mm->mmap_sem);
+	mmput(mm);
 
 	trace_binder_unmap_kernel_start(alloc, index);
 
-	unmap_kernel_range(page_addr, PAGE_SIZE);
 	__free_page(page->page_ptr);
 	page->page_ptr = NULL;
 
@@ -995,7 +952,7 @@
 	mutex_unlock(&alloc->mutex);
 	return LRU_REMOVED_RETRY;
 
-err_down_write_mmap_sem_failed:
+err_down_read_mmap_sem_failed:
 	mmput_async(mm);
 err_mmget:
 err_page_already_freed:
@@ -1052,3 +1009,175 @@
 	}
 	return ret;
 }
+
+/**
+ * check_buffer() - verify that buffer/offset is safe to access
+ * @alloc: binder_alloc for this proc
+ * @buffer: binder buffer to be accessed
+ * @offset: offset into @buffer data
+ * @bytes: bytes to access from offset
+ *
+ * Check that the @offset/@bytes are within the size of the given
+ * @buffer and that the buffer is currently active and not freeable.
+ * Offsets must also be multiples of sizeof(u32). The kernel is
+ * allowed to touch the buffer in two cases:
+ *
+ * 1) when the buffer is being created:
+ *     (buffer->free == 0 && buffer->allow_user_free == 0)
+ * 2) when the buffer is being torn down:
+ *     (buffer->free == 0 && buffer->transaction == NULL).
+ *
+ * Return: true if the buffer is safe to access
+ */
+static inline bool check_buffer(struct binder_alloc *alloc,
+				struct binder_buffer *buffer,
+				binder_size_t offset, size_t bytes)
+{
+	size_t buffer_size = binder_alloc_buffer_size(alloc, buffer);
+
+	return buffer_size >= bytes &&
+		offset <= buffer_size - bytes &&
+		IS_ALIGNED(offset, sizeof(u32)) &&
+		!buffer->free &&
+		(!buffer->allow_user_free || !buffer->transaction);
+}
+
+/**
+ * binder_alloc_get_page() - get kernel pointer for given buffer offset
+ * @alloc: binder_alloc for this proc
+ * @buffer: binder buffer to be accessed
+ * @buffer_offset: offset into @buffer data
+ * @pgoffp: address to copy final page offset to
+ *
+ * Lookup the struct page corresponding to the address
+ * at @buffer_offset into @buffer->user_data. If @pgoffp is not
+ * NULL, the byte-offset into the page is written there.
+ *
+ * The caller is responsible to ensure that the offset points
+ * to a valid address within the @buffer and that @buffer is
+ * not freeable by the user. Since it can't be freed, we are
+ * guaranteed that the corresponding elements of @alloc->pages[]
+ * cannot change.
+ *
+ * Return: struct page
+ */
+static struct page *binder_alloc_get_page(struct binder_alloc *alloc,
+					  struct binder_buffer *buffer,
+					  binder_size_t buffer_offset,
+					  pgoff_t *pgoffp)
+{
+	binder_size_t buffer_space_offset = buffer_offset +
+		(buffer->user_data - alloc->buffer);
+	pgoff_t pgoff = buffer_space_offset & ~PAGE_MASK;
+	size_t index = buffer_space_offset >> PAGE_SHIFT;
+	struct binder_lru_page *lru_page;
+
+	lru_page = &alloc->pages[index];
+	*pgoffp = pgoff;
+	return lru_page->page_ptr;
+}
+
+/**
+ * binder_alloc_copy_user_to_buffer() - copy src user to tgt user
+ * @alloc: binder_alloc for this proc
+ * @buffer: binder buffer to be accessed
+ * @buffer_offset: offset into @buffer data
+ * @from: userspace pointer to source buffer
+ * @bytes: bytes to copy
+ *
+ * Copy bytes from source userspace to target buffer.
+ *
+ * Return: bytes remaining to be copied
+ */
+unsigned long
+binder_alloc_copy_user_to_buffer(struct binder_alloc *alloc,
+				 struct binder_buffer *buffer,
+				 binder_size_t buffer_offset,
+				 const void __user *from,
+				 size_t bytes)
+{
+	if (!check_buffer(alloc, buffer, buffer_offset, bytes))
+		return bytes;
+
+	while (bytes) {
+		unsigned long size;
+		unsigned long ret;
+		struct page *page;
+		pgoff_t pgoff;
+		void *kptr;
+
+		page = binder_alloc_get_page(alloc, buffer,
+					     buffer_offset, &pgoff);
+		size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
+		kptr = kmap(page) + pgoff;
+		ret = copy_from_user(kptr, from, size);
+		kunmap(page);
+		if (ret)
+			return bytes - size + ret;
+		bytes -= size;
+		from += size;
+		buffer_offset += size;
+	}
+	return 0;
+}
+
+static int binder_alloc_do_buffer_copy(struct binder_alloc *alloc,
+				       bool to_buffer,
+				       struct binder_buffer *buffer,
+				       binder_size_t buffer_offset,
+				       void *ptr,
+				       size_t bytes)
+{
+	/* All copies must be 32-bit aligned and 32-bit size */
+	if (!check_buffer(alloc, buffer, buffer_offset, bytes))
+		return -EINVAL;
+
+	while (bytes) {
+		unsigned long size;
+		struct page *page;
+		pgoff_t pgoff;
+		void *tmpptr;
+		void *base_ptr;
+
+		page = binder_alloc_get_page(alloc, buffer,
+					     buffer_offset, &pgoff);
+		size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
+		base_ptr = kmap_atomic(page);
+		tmpptr = base_ptr + pgoff;
+		if (to_buffer)
+			memcpy(tmpptr, ptr, size);
+		else
+			memcpy(ptr, tmpptr, size);
+		/*
+		 * kunmap_atomic() takes care of flushing the cache
+		 * if this device has VIVT cache arch
+		 */
+		kunmap_atomic(base_ptr);
+		bytes -= size;
+		pgoff = 0;
+		ptr = ptr + size;
+		buffer_offset += size;
+	}
+	return 0;
+}
+
+int binder_alloc_copy_to_buffer(struct binder_alloc *alloc,
+				struct binder_buffer *buffer,
+				binder_size_t buffer_offset,
+				void *src,
+				size_t bytes)
+{
+	return binder_alloc_do_buffer_copy(alloc, true, buffer, buffer_offset,
+					   src, bytes);
+}
+
+int binder_alloc_copy_from_buffer(struct binder_alloc *alloc,
+				  void *dest,
+				  struct binder_buffer *buffer,
+				  binder_size_t buffer_offset,
+				  size_t bytes)
+{
+	return binder_alloc_do_buffer_copy(alloc, false, buffer, buffer_offset,
+					   dest, bytes);
+}
+